Trace Amounts Of Phosphorus Research Articles

Interaction of Molybdo-Phosphoric and Molybdo-Antimono-Phosphoric Heteropoly Acids with Silica Gels Modified with Aliphatic and Heterocyclic Quaternary Ammonium Salts

The interaction of molybdo-phosphoric and molybdo-antimonophosphoric heteropoly acids with aliphatic (tetradecylammonium nitrate and trinonyloctadecylammonium iodide) and heterocyclic (lucigenine and safranine) quaternary ammonium salts immobilized onto silica has been studied using adsorption and spectroscopic methods. It has been shown that the formation of ionassociates between the quaternary ammonium cations and the heteropoly anions is accompanied by their interaction with surface silica groups which accounts for the tight binding of heteropoly acids to the surface. Such interfacial reactions can successfully be applied to the development of spectroscopic and semi-quantitative visual test techniques for detecting trace amounts of phosphorus and antimony.

Determination of trace phosphorus in high purity tantalum materials by inductively coupled plasma mass spectrometry subsequent to matrix separation with on-line anion exchange/coprecipitation.

An on-line matrix separation/inductively coupled plasma mass spectrometry (ICP-MS) method is proposed for the determination of trace amounts of phosphorus in high purity tantalum metal, tantalum (V) oxide, and tantalum pentaethoxide. In the present method, the matrix tantalum in the sample solution was adsorbed on the anion exchange resin, and phosphorus (phosphate ion) was eluted with the carrier solution of HF and HNO3 mixture. Then, the effluent solution was subsequently mixed with bismuth solution and aqueous ammonia solution to coprecipitate phosphate together with bismuth hydroxide. The precipitate formed was collected on the in-line membrane filter to wash out nitric acid with pure water, and then dissolved with hydrochloric acid. The obtained phosphorus sample solution was introduced directly into the nebulizer of ICP-MS for the determination of phosphorus. Phosphorus was determined at the molecular ion signal of 31P16O+ (m/z 47). The detection limit (3sigma) of phosphorus in the present method was 1.3 ng mL(-1) as the sample solution basis, and the relative standard deviation for 30 ng mL(-1) of phosphorus in the standard solution was 4.3% in the replicate measurements (n=11). The present method was applied to the analysis of high purity tantalum materials. The concentrations of phosphorus in tantalum samples were in fairly good agreement with those obtained by glow discharge mass spectrometry (GDMS).

Determination of trace amounts of phosphorus in silicate materials by simultaneous inductively coupled plasma atomic emission spectrometry

Inductively coupled plasma atomic emission spectrometry (ICP-AES) implemented on a simultaneous spectrometer was used for the determination of trace amounts of phosphorus in rocks, soils and sediments. Samples were decomposed by using a mixture of concentrated hydrofluoric, perchloric and nitric acid in Teflon beakers. Overlap of emissions from other elements present in the samples with the polychromator spectral line at 214.914 nm for phosphorus was studied. The corresponding inter-element coefficients for overlap correction were determined and the optimum position for background readings was established. The limit of determination achieved was 24 ppm referred to the solid sample. The proposed method was tested by applying it to the analysis of rock, soil and sediment certified reference materials, and determining its short-time precision and method precision, which turned out to be 0.24–0.68% and 1.70–4.16%(relative standard deviation), respectively.

Determination of trace amounts of phosphorus by laser excited time-resolved fluorimetry

Phosphorus was determined as orthophosphate via formation of the phosphorus–vanadium–molybdenum heteropoly acid ion-association complex with lactic acid–6,9-diamino-2-ethoxyacridine (livanol). The extraction–flotation method was used to separate and concentrate the complex, after which laser-excited time-resolved fluorimetry was employed to determine phosphorus in samples of water, plants, organisms, soils and rocks. The method showed good linearity over the phosphorus concentration range 0–0.5 µg ml–1. Samples were also taken from bovine serum albumin (containing 130 µg ml–1 of phosphorus); the relative standard deviation was less than 5%(n= 10) and the detection limit was 0.7 ng ml–1.

The Spectrophotometric Determination of Phosphorus with o-Hydroxyhydroquinonephthalein and Iron(III)

Abstract On this basis of the coloration formed with o-hydroxyhydroquinonephthalein, an anionic dye, and iron(III) in aqueous media, trace amounts of phosphorus(as orthophosphate ion) was determined. A sample solution containing posphorus and the reagent blank in an amber-colored test tube with a stopper were heated at 40 °C for 20 min in the presence of poly(oxyethylene)sorbitan monolaurate, a nonionic surfactant, as a dispersion agent. Beer’s law was obeyed over the range of ≈1 μg/10 cm3 of phosphorus, and the apparent molar absorptivity of the complex was 2.5×105 dm3 mol−1 cm−1 at 610 nm. The present method was applied to the determination of total phosphorus in water — a sample solution containing small amounts of metal ions —, and the recovery percentage was satisfactory, about 95%. Other compounds containing phosphorus such as 5′-adenosine triphosphate could also be determined without a preliminary treatment.

Determination of trace amounts of phosphorus in organic compounds by wickbold combustion

Wickbold combustion in a standard quartz apparatus with a suction burner is suitable for phosphorus determination in acetonesoluble materials if the samples are burned together with an organic halide, e. g. carbon tetrachloride. Probably phosphorus halides are formed which pass through the hot parts of the apparatus fast enough not to react with the quartz walls. The recovery is 95–100% for amounts of phosphorus up to 3.5 mg per combustion.

Determination Of Phosphorus In Low Alloy Steels By Inductively Coupled Plasma Emission Spectrometry

Abstract Trace amounts of phosphorus in various low alloy steels were determined by ICP emission spectrometry. Coexisting copper, a spectroscopically interfering element, was removed by solvent extraction with DBDTC. The proposed method is simple and does not require a monochromator with high resolving power nor a vacuum system.

Creep crack growth in 2¼CrMo weld metals: the suppression of trace element embrittlement by creep strength effects

It has been shown previously (Gooch et al . 1977) that bainitic steels of the 1/2 Cr 1/2 Mo 1/4 V type are severely embrittled in the creep range by the presence of trace amounts of phosphorus, arsenic, tin and antimony. These steels are commonly welded by using 2 1/4Cr1Mo electrodes and problems of weld metal cracking transverse to the welding direction have been experienced both after post-weld heat treatment and during subsequent service. It has been suggested (Bruscato 1970) that trace element embrittlement also may be operative in 2 1/4Cr1Mo weld metal. In the present work, creep crack growth tests were performed in vacuum at 565 °C on single edge notched tension specimens of four commercial manual metal arc weld metals with varying carbon (0.02-0.06%), phosphorus (0.012-0.031%) and arsenic (0.019-0.050%) levels. Specimens were tested either after tempering at 650 or 700 °C, or after stress relaxation (before notching) at the same temperatures. Complementary creep rupture tests were performed on tempered material.

Isolation and characterization of the lipopolysaccharide of Thiocapsa roseopersicina.

The lipopolysaccharide from Thiocapsa roseopersicina was isolated by phenol/water, being found in the water phase. It is cleaved into a polysaccharide moiety (degraded polysaccharide) and lipid A by hydrolysis with 10% acetic acid (100 degree C, 3 h). D-Mannose, L-rhamnose, 3-amino-3, 6-dideoxy-D-galactose and D-glucose are the major constituents of the degraded polysaccharide. 2-O-Methyl-L-rhamnose, 3-O-methyl-D-mannose, D-galactose, glucosamine and quinovosamine are minor constituents. D-Glycer-D-manno-heptose (tentatively identified) and 3-deoxy-D-manno-octulosonic acid were detected in only small amounts. Conspicuously, lipid A from T. roseopersicina contains a neutral sugar, D-mannose, in addition to D-glucosamine, as had been observed with lipid A from Chromatium vinosum D. Major fatty acids are beta-hydroxymyristic and lauric acids. Only trace amounts of phosphorus were found indicating this lipid A to be free of phosphate. The lipopolysaccharide of T. roseopersicina represents the O-antigen of the strain. It reacts with antisera prepared against living or heat-killed cells in passive hemagglutination.

A new extraction–spectrophotometric method for the determination of phosphate

A new extraction–spectrophotometric method has been developed for the determination of trace amounts of phosphorus as orthophosphate. The method is based on the chemistry of 12-tungstophosphoric acid, H3PW12O40 (TPA). In the procedure, orthophosphate is converted quantitatively to TPA in aqueous solution at a tungstate–phosphate molar ratio ≥24, in the pH range 1.2 to 1.9 and in the temperature range 60 to 100 °C. The TPA is subsequently extracted into n-amyl alcohol and its absorbance measured at 267 nm. Beer's law is followed up to at least 25 µg/ml P. The method is less prone to solution conditions and species interference (especially As(V) and Si(IV)) than the widely used molybdenum-blue methods and is competitive in terms of sensitivity, precision, and accuracy. The TPA method was applied successfully to the determination of phosphate in a variety of phosphorus-containing specimens including natural waters, ores, and alloys.Based on potentiometric and spectrophotometric studies, a scheme which accounts for the observed heptaproticity of TPA is proposed.

O-phosphoserine as a constituent of polypeptide chains of bovine fibrinogen

The subunits chains obtained by sulphitolysis of bovine fibrinogen have been separated by column chromatography into four fractions; I, II, III and IV, corresponding to the γ-1, γ-2, β(B) and α(A) ∗ ∗ The nomenclature recommended by the International Committee on Haemostasis and Thrombosis (Washington 1967) for the three peptide chains in fibrinogen is α (A), β (B), and γ. chains, respectively. From the last two fractions phosphoserine was isolated by thin-layer chromatography. In Fractions I and II only trace amounts of phosphorus were detected. The role of phosphorus in the conversion of fibrinogen to fibrin is discussed.

The determination of trace amounts of phosphorus by a double amplification method

The determination of trace amounts of phosphorus by a double amplification method